Since winning his seat in 1980, 12-term Rep. Tom Lantos (D-Calif.) has rarely had to sweat re-election.

The 13th run, however, is proving more difficult for the top Democrat on the House International Relations Committee.

The 76-year-old Congressman is facing a surprisingly strong primary challenge in his San Francisco-area district from a 27-year-old lawyer and political novice, Ro Khanna.

Khanna may ultimately find that he doesn’t have the resources — or gravitas — to compete against Lantos. But the race has clearly turned into one of the sleepers of the March 2 California primary.

“This is going to be the most competitive race in the state,” Khanna boasted.

The primary also has some of the ideological overtones of the just-completed mayoral election in San Francisco, which saw a liberal Democratic member of the city’s Board of Supervisors, Gavin Newsom, narrowly triumph in a runoff over Board President Matt Gonzalez, a member of the Green Party. Gonzalez, in fact, has endorsed Khanna, while Newsom is siding with Lantos.

But while that election was largely fought over issues like how to treat the homeless and whether Democratic officeholders have become too cozy with the business establishment, Khanna is attacking Lantos for two high profile votes — authorizing President Bush to go to war in Iraq and supporting the Patriot Act in the wake of the Sept. 11, 2001, terrorist attacks.

He calls Lantos “out of touch with the Democratic mainstream” in the district, which takes in southwestern sections of San Francisco and adjoining San Mateo County, and says the incumbent’s votes are emblematic of his arrogance toward his constituents.

While maintaining a decidedly liberal voting record, Lantos makes no secret of his alliances with Bush and House Majority Leader Tom DeLay (R-Texas) on matters of foreign policy. A former economics professor and commentator on world affairs, Lantos counts Bush’s National Security Adviser Condoleezza Rice among his friends, dating from her days as provost at Stanford University.

“I think defeating Tom Lantos is going to send a message to Democrats around the country about the direction we should be going in,” Khanna said.

But Lynne Weil, a spokeswoman for Lantos, said that her boss has called for modifications to the Patriot Act since it was first enacted. She said the Congressman’s votes on Iraq and homeland security are well-known to his constituents, and noted that they were taken before the 2002 election, which he won easily.

“To continue to turn the clock back to both votes, taken in October 2001 and October 2002, without looking at what the Congressman has said since then is simply unfair,” Weil said.

Despite Lantos’ enduring popularity — and his compelling life story as a Holocaust survivor from Hungary who joined the resistance as a teenager — the Iraq war is highly unpopular in the Bay area, and Khanna is pushing it aggressively. That, coupled with a sense of political uncertainty in San Francisco — and in California — makes Lantos’ position less secure than it ought to be.

Term limits in the city and state are throwing out several veteran officeholders, most notably just-retired San Francisco Mayor Willie Brown (who is also a former state Assembly Speaker) and his close ally, state Senate President Pro Tem John Burton (D). San Francisco’s longtime district attorney was recently defeated by Kamala Harris, a half-black, half-Indian woman in her 30s. Gonzalez and Newsom are also both in their 30s.

“Among the liberals, there’s a sense that Democratic leaders are too comfortable, too close to business,” said David Binder, a San Francisco-based pollster. “And there is this sense of fatigue over long-term incumbents. Voters are expecting new faces in their offices.”

But Lantos’ allies are suggesting that Khanna is too fresh a face. A Yale Law School graduate who grew up in Philadelphia, Khanna has lived in San Francisco for three years. He interned for political officeholders and campaigns while he was in college and law school and has been active in anti-war groups, but has scant political experience and just moved into the 12th district eight months ago.

While maintaining that he “respects [Lantos’] life history,” Khanna is trying to sell voters his own story as well. He’s hoping that they’ll respond to his call to elect the second Indian-American in history to Congress.

Khanna said he has 40 paid workers in the field to gin up the vote and is confident that he will do well. Weil said that even if that many people are working for Khanna, his campaign has “created the illusion of more noise and support than we believe is really there.”

Lantos certainly has a big money advantage. He had $1.2 million in the bank as of Feb. 11, and spent $280,000 in the first six weeks of the year, mostly for regular slick mailings into Democratic homes (neither campaign is likely to buy TV ads in the diffuse, expensive San Francisco market).

Khanna had $95,000 on hand as of Feb. 11, after raising $140,000 during the first six weeks of the year, though he said he hopes to spend a total of $400,000 on the primary.

“My gut,” said pollster Binder, “tells me that Lantos will survive it.”